Chronograph.



PATENTED MAR. 10, 1908.

E. B. MERRIAM.

GHRONOGRAPH.

APPLICATION FILED JULY 22, 1904.

Wk mmw Nam Er VP W B a r H b a E s s E UNITED STAIES PATENT OFFICE.

EZRA B. MERRIAM, OF SCHENEGTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRICCOMPANY, A CORPORATION OF NEW YORK.

CHRONOGRAPH.

To all whom it may concern:

Be it known that I, EZRA B. MERRIAM, a citizen of the United States,residing at Schenectady, in the county of Schenectady and State of NewYork, have invented certain new and useful. Im rovements inChronographs, oi which the iollowing is a speciii cation.

This invention relates to apparatus for making simultaneous records, onone or more traveling surfaces, of the ex iration of time intervals andother data whic i it is desired to compare.

lrlerctofore in nearly all chronographic apparatus of which I am aware,the measure ment of the time has been done by a clock, whose operation.has been recorded. either mechanically or electrically on the recordelement. It has also been proposed to photographic-ally record thevibrations of a tuning ork whose number of vibrations per second. for agiven musical note are known. My invention difl'ers from both of thesemodes of gettin an. accurate time record, and is in many ways i arsimpler. Inasmuch as the modern alternating-current generator supplies acurrent whose frequency is very constant, I take advantage of this factby using such a current to energize an electromagnet whose armaturecarries a recording element, such as a marking point resting on atraveling record ele ment. The point will trace a continuous line, butat every alternation of the current the armature is-attracted andconsequently the pressure it exerts on the point is alternately heavyand light. This causes said point to produce a line which is composer.of a series of alternately heavy and light portions correspondingexactly with the frequency of the current, and since this is known, itis easy to read the elapsed time down to fractions of a secondcorresponding with the frequency.

In the accompanying drawing, Figure 1 is a perspective view of an apiaratus embodying my'invention; Fig. 2 ilustrates a 'ortion of a recordFig. 3 is an. end elevation; and Fig. 4- is a section of a portion ofthe electromagnet and its armature.

On a suitable base 1 is erected a table over which the record strip orstrips 3 can be drawn by suitable mechanism from rolls 4. Above eachstrip is located one or more up right guides 5, preferably tubes ofnon-11mg- Specification of Letters Patent.

Application filed. July 22,

netic material such as brass, depending from a transverse bridge 6.

In each tube is a weight of soft iron carry ing on its bottom a markingpoint resting on the record strip. The lower end of the tube does nottouch the strip, there being suilicient space between the tube and thetable to permit the strip to travel freely. Immediately below one ofsaid tubes, with its axis in line with that of the tube, is an uprightelectromagnet 7, whose coil is in circuit with analternating-currentgenerator 8 of known frequency. At every alternationof the current, the armature or weight 9 in line with the core of saidelectromagnet is attracted strongly by said magnet, so that the markingpoint bears more heavily on the record strip. The result is that a line10 is drawn which is made of alternate light and heavy portions equallyspaced and correspondingexactlywith the frequency of the current. Ifthis is a cycle current, there will be 120 dots or short dashes madeevery second on the strip. It is evident that these will be independentof the speedof the strip, so that any irregularity in the feed of saidstrip is immaterial Other records may be made on said strip, or onparallel strips simultaneously with the time record. These additionalrecords may be made mechanically or electrically. In. the drawing, Ihave shown two electromagnets, 11 12, mounted on the bridge 6 andprovided with pivoted armatures 13 carrying rods 14. con nected withweighted marking points 15 in the guidestubes 5. Each electromagnet maybe in circuit with some apparatus whose per formance during a given timeit is desired to record, such for example, as the s 768d of stroke on anoil switch, the time when the parts of' a motor-starting switch start,the time it takes a spring to compress, the dura tion of a short-circuiton a given machine, the time necessary for a motor or other piece ofapparatus to obtain a known speed, the calibration of the time limitrelays of an elebtric system, the acceleration of vehicles, timerequired for various metals to fuse under the action of electriccurrent, etc, and so on.

In accordance with the provisions of the patent. statutes, I havedescribed the principle of operation of my invention, together with thea paratus which I now consider to represent t e best embodiment thereof;but I desire to have it understood that the appasaid table, a

ratus shown is merely illustrative, and that the invention can becarried out by other means.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is,

1. Means for recording the frequency of an alternating current,comprising an electromagnet connected to be energized by said current, atable above the same, a bridge over guide de ending from said bridge inline with said e ectromagnet, and a loose weight insaid guide carrying amarking point.

2; Means for making records, comprising a traveling record carrier, amain recording device cooperating therewith, a time recording deviceaving a movable part, a source of alternating current of knownfrequency, and

alternating current of known frequency and a marking device connected tobe actuated 25 by said current for roducing alternatin light and heavymarks corresponding witE the cycles of said alternating current of knownfrequency.

1 In witness whereof, I have hereunto set my 30 hand this 20th day ofJuly, 1904.

EZRA B. MERRIAM Witnesses:

BENJAMIN B. HULL, HELEN ORFORD.

